Along with scaling of semiconductor devices, shortening of the wavelength of light sources used for light exposure apparatuses is progressing. Nowadays, a light exposure apparatus (EUV light exposure apparatus) using extreme ultraviolet light having a wavelength of about 100 nm or less (Extreme Ultraviolet Light: which will be referred to as EUV light, hereinafter) is becoming applied to manufacturing of semiconductor devices. Since EUV light is attenuated in the atmosphere, light exposure using the same is performed in a vacuum chamber, in general. Accordingly, an EUV light exposure apparatus of the mainstream type uses an electrostatic chuck to hold the rear face of a mask.
In the case of the type using an electrostatic chuck to hold the rear face of a mask, the contact area between the rear face of the mask and the holding mechanism tends to increase, as compared with a type using a vacuum chuck. This increases the possibility that, when particles are deposited onto the rear face of the mask or the holding mechanism, the particles are sandwiched therebetween. As a result, the height of the mask is partly changed, and its position for transferring patterns onto a wafer ends up being shifted. Further, if particles are deposited onto the face of the mask including light exposure patterns thereon, the particles are transferred as patterns, and pattern defects are thereby generated.
As described above, if particles are deposited onto the mask used in the EUV light exposure apparatus, they will have great influence on the light exposure. However, conventionally, there is proposed an apparatus for examining the presence and absence of foreign substances deposited on a test substrate, but there is not proposed a mechanism for monitoring particles deposited on a mask in an EUV light exposure apparatus.